The current trend towards increasing use of sophisticated electronic systems in the automotive arena shows a number of parallels with the aviation industry of the recent past. The authors' perspective from a systems company at the forefront of avionic systems development is that a systems approach is not yet being fully adopted within the automotive industry. The authors briefly discuss the develo...
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The author briefly describes the requirements of an automotive sensor system and demonstrates how a simple FMCW radar can fulfil the specified requirements. In considering the cost of implementing such a system, emphasis is placed on the use of technology as is available at this time. A moderate improvement in sweep linearity enables the system to fulfil all signal to clutter requirements. This ca...
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The authors discuss the requirements of a tyre pressure sensor. They then describe a sensor in which a wheel-mounted mechanism produces a displacement as a function of tyre pressure. This displacement is used to vary the separation of a pair of permanent magnets. The position of these magnets is sensed from the vehicle chassis by means of a Hall probe. The thermal compensation for the sensor, and ...
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A sensor, operating as a variable capacitance cell, has been developed for determining the ratio of methanol to petrol in fuel mixtures, through the measurement of the dielectric constant. When operated as part of a Digital Autoplex circuit, the sensor provides an approximately linear output across the full range of petrol/methanol mixture ratios, and is insensitive to variations in conductivity. ...
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Amorphous materials in the ribbon or wire form have been commercially produced. There are two basic types, highly magnetostrictive, ideal for stress sensing, and zero magnetostrictive, ideal for proximity devices. A typical sensor uses less than 1 g of the material. The author discusses the use of these materials in force transducers, rotational speed sensors, noncontact torque sensors, vibration ...
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The author discusses the development of the yaw rate sensor for braking systems. A vibrating structure gyroscope is used for the sensor. The author briefly describes the operating principles of the sensor which are based on a resonating piezoelectric cylinder
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The author discusses the limitations on a strain gauge for rotating or moving mechanisms. The author then discusses the use of a surface acoustic wave transducer to overcome these limitations. The principles of operation are briefly discussed. Torque (radial strain) sensors are also briefly discussed
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The authors describe the development of two automotive sensors by a co-operation between First Inertia Switch Ltd. and Sira R&D. The sensors in question were an automatic headlamp dipswitch, and a steering wheel rotation sensor. In both cases FISL provided the impetus and marketing strengths to maintain focus on the requirements, and Sira provided a design and development resource to meet the ...
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Speed-over-ground (SOG) sensors can provide a potentially important input to advanced vehicle control systems, including instrumentation, navigation, braking, traction and steering. The basic requirements for automotive use include low cost, a speed range of 1-50 m/s, and a temperature range of -40-+85°C. A measuring rate of 10-50 Hz is needed in some applications. Exposure to rain or contamin...
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The authors mention three techniques based upon spectral analysis for improving radar speedometer accuracy. These are FFT centre of gravity estimation, correlation technique, and super-resolution algorithms. Each of the techniques offers the potential for correcting for terrain bias error and, because of the increased amount of information available compared with a zero crossing approach, each len...
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The author describes the application of an optical torque sensor in a concept electric power assisted steering (EPAS) system for small cars which has been developed at Lucas Advanced Engineering Centre. A novel design of sensor enables the required performance to be obtained while still having the potential of low-cost manufacture compatible with the automotive market. An EPAS system uses an elect...
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